Short-term Investments (Tables)

9 Months Ended

Sep. 30, 2016

Investments, Debt and Equity Securities [Abstract]

Short-Term Investments Available-for-Sale Securities

Short-term investments consisted of available-for-sale securities as follows (in thousands):

Type of securities as of September 30, 2016	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
Corporate debt securities	$	29,811	$	1	$	(17	)	$	29,795
U.S. government-related debt securities	13,315		7		(1		)	13,321
Total available-for-sale securities	$	43,126	$	8	$	(18	)	$	43,116

Type of securities as of December 31, 2015	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value
Corporate debt securities	$	26,116	$	—	$	(28	)	$	26,088
U.S. government-related debt securities	1,101		—		(1		)	1,100
Total available-for-sale securities	$	27,217	$	—	$	(29	)	$	27,188

Fair Values of Available-for-Sale Securities by Contractual Maturity

The fair values of available-for-sale securities by contractual maturity were as follows (in thousands):

	September 30, 2016		December 31, 2015
Maturing in one year or less	$	33,799	$	27,188
Maturing in one to three years	9,317		—
Total available-for-sale securities	$	43,116	$	27,188